Crystal gap and holder



July 28, 1953 c, w, D s 2,647,210

' CRYSTAL CAP AND HOLDER Filed May 11, 1951 INVENTOR CHARMS W.0AV/$ ATTORNEY Patented July 28, 1953 UNITED STATES PATENT OF F I CE CRYSTAL GAP AND HOLDER Charles Davis, Nutley, l, .ass ig'nor to Federal Telecommunication Laboratories, Inc., Nutley, N. J., 'a. corporation or Delaware Application May 11, 1951, Serial 225,893

This invention relates to holders for crystals such .as used in high frequency communication systems.

In communication systems employing waveguides and cavity resonators it is often desirable to dispose a crystal in the waveguide or cavity resonator as apart of the electrical circuit thereof. This is commonly done by providing a crystal holder mounted in a wall of the electrical apparatus. Heretofore, the crystal holders are made to receive the crystal in a removable grippingrela-tion. While the-crystal may be removed from such holders, it-is d-ifiicult for a repairman to remove the crystal without damaging it. "If a screwdriver or other tool is used to pry it out of the holder, there is danger of the crystal broken, dropped or lost.

One of the objects of this invention is to provide an improved holderfor crystal units for electrical apparatus whereby the crystal is supported in proper "relation in the ap aratus and an element of the holder is always present for use in removing and/or inserting crystals.

A further object is to provide a crystal holder in two parts, the first part to receive and support the crystal and the second part for gripping the crystal for insertion and removal from the first part.

The crystal holder in accordance with my invention comprises a hollow cylindrical member adapted to be mounted in an opening in the wall of a waveguide or other electrical apparatus, the cylindrical member having at its outer end a plurality of circumferentially spaced fingers or tines adapted to receive and support a crystal. Certain of the fingers are made longer than others to determine the positioning of the crystal, the crystal unit being provided with a rim at one end which is engaged by the longer fingers. The shorter fingers provide a space beneath the rim whereby a recessed portion of a closure element may be received to grip the crystal unit. With the crystal unit thus gripped by the closure element it may be inserted or removed and replaced in the holder at will.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood, by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

Fig. 1 shows the holder in longitudinal crosssection with a crystal held therein in coupled relation with a waveguide;

Fig. 2 is a view .in cross-section taken substantially along line 2--2 :of Fig. 1;

Fig. :3 is a view in elevation with parts in section-showing the closure element crystal gripping position;

Fig. :4 is a view :in plan of the crystal holding member; and

Fig. ;5 is :a view in side elevation of the :upper portion of the crystal holding member.

Referring to the drawings, the electrical apparatus illustrating the use of the crystal holder of this invention is shown to be a waveguide 1 .having an ropening :2 in a wall thereof. The crystal holding member :3 is shown 1170 be a hollow cylindrical member receivable in the opening 2 where- 'by it :may be sealed to the waveguide by brazing "or welding. The outer end :of the member 3 is provided with a plurality of fingers 4, 5, 6, l, 8 and i9, the opposed fingers 4 :and I being longer :than'the other fingers 5, 6, 8 and 9. The crystal unit SILD is provided at 20118 :end thereof with radially outwardly extending portions in the form of a rim II which is adapted to be engaged by the longer fingers 4 and 1 whereby a space is provided between the rim H and the shorter fingers 5, 6, 8 and 9. The fingers 4 to 9 are each provided with inwardly disposed projections to engage and grip the sides of the crystal unit.

The outer surface of the crystal holder member 3 is provided with threads I2 to threadably receive a closure element [3 which when threadably received on the member 3 is adapted to engage the upper end of the crystal ill to hold it tightly against the upper ends of the fingers 4 and I. The crystal Il! may be inserted by hand when the closure element I3 is removed from the member 3. To remove the crystal In from the holder 3 considerable exertion is required if one uses his fingers. If he does he may break his finger nails and have to resort to using a screwdriver which is apt to result in damage to the crystal. According to one of the features of my invention I make the closure element so that it can be used for this purpose. The outer end of the closure element I3, for example, is provided with a T-shaped recess l4 having two inwardly projecting portions 15 and [6. By sliding the T-shaped recess l4 crosswise onto the rim portion ll of the crystal unit with projections l5 and I6 beneath the rim in the spaces provided by the shorter fingers 5, 6, 8 and 9, the crystal will be held in a tight grip. By lifting upwardly on the closure element I3 the crystal unit is easily removed from the holder member and the coupling element l1 with which the crystal terminal 18 is releasably connected.

To insure against the loss of the closure element l3, the element is provided with a groove IE to receive a chain connecting ring 20 to which a chain 2| is connected and anchored to a similar ring 22 received in the groove 23 on the crystal holder 3.

From the foregoing it will be clear that the holder is made to receive and support a crystal unit in proper electrical connection between a wall of the waveguide and the coupling conductor l1, and further, a closure element is provided for the holder which may be used to grip the crystal unit for insertion and removal from the holder. This gripping element being chained to the holder member provides means for holding the crystal while it is removed from the holder 3 without danger of it being lost during repair operations; The element I3 may thus be used to return the crystal to its position in the holder 3 whereupon it is slid sideways from the crystal unit and by inverting it, the element may be threadably received onto the holder 3 as a closure element.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention, as set forth in the objects thereof and in the accompanying claims.

I claim:

1. A holder for crystal units of cylindrical shape having a laterally projecting rim at one end, comprising a hollow cylindrical member having circumferentially spaced fingers at one end thereof to receive said crystal unit with the rim of the unit engaged by the upper ends of certain of said fingers, other of said fingers being shorter to provide alspace between'such certain fingers and the rim of the unit, and a crystal gripping element having inwardly projecting portions receivable in the spaces between the short fingers and the rim whereby the crystal may be gripped for removal from said member.

2. In electrical apparatus having a wall with an opening for the reception of a crystal, a cylindrical member disposed adjacent said opening, said member having a plurality of fingers at its outer end for supporting a crystal unit receivable therein, said member having threads on the outer surface thereof and a closure element receivable over said fingers in threaded engagement with said member, certain of the fingers of said member being longer than other of said fingers and said crystal unit is provided with a rim at one end adapted to be engaged by the upper ends of said longer fingers.

3. In electrical apparatus according to claim 2, wherein said closure element includes a T-shaped recessed portion adapted to receive the rim of said crystal unit whereby the crystal unit may be removed from said member by lifting said closure element.

CHARLES W. DAVIS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 607,526 Schrader July 19, 1898 2,436,830 Sharpless Dec. 14, 1948 2,456,305 Nelson Dec. 14, 1948 2,549,820 Kinzle Apr. 24, 1951 2,555,151 Noyes, Jr May 29, 1951 FOREIGN PATENTS Number Country Date 604,270 Great Britain July 1, 1948 OTHER REFERENCES Proc. I. R. E. Vol. 35, page 1185, November 1947. 

